That's almost the same way it went for me on a recent test/deca cycle/ldex (with a 2-week adrol/winny lead-in); went up 17 lb quickly (within the first 4-5 weeks) and stabilized -- the rest of the cycle stayed about the same weight, but muscle quality and aesthetics improved and I lost some fat.
Properly gauging post-cycle success was difficult with this one because I got fucking strep the first week that I was to begin post-cycle therapy (talk about a pisser!); I couldn't eat 4 days (fevers, puking, etc.) and I lost about 8 lb immediately.
As soon as I started my post-cycle therapy (and eating again), I stabilized and haven't lost anymore weight. I'm near the end of my 3rd week post cycle (5 wks after last shot of enanthate -- I quit the deca in wk 5 of 10) and I've gained a few pounds back. My strength levels remain nearly what they were on cycle (see my carao comment below) and my body is much improved aesthetically.
I didn't try the HCG this time around -- but I did throw in maca at 1.5 grams/day, carao extract (which I believe is making a HUGE difference) at 3 tsp/day, 5htp at 100 mg/day, inositol at 3-6 grams/day and nolva over 3 weeks reverse pyramiding from 40 mg/day down to 10 mg/day. As a side note, sex drive is through the roof.